Polyamides and copolyamides containing 2,2&#39;,4,4&#39;,6,6&#39;-hexamethyl-3,3&#39;-diaminobiphenyl moieties

ABSTRACT

Novel polyamides and copolyamides prepared from 2,2&#39;4,4&#39;6,6&#39;-hexamethyl 3,3&#39;-diaminobiphenyl (3,3&#39;-M 2  DAM) and aliphatic or aromatic diacids. 3,3&#39;-M 2  DAM and a mixture of other aliphatic or aromatic diamines may also be suitably used to react with the diacids. These novel polyamides and copolyamides are useful in preparing molded articles, fibers, films, laminates and coatings.

BACKGROUND OF THE INVENTION

Field of the Invention

The field of the invention relates to polyamides and copolyamides prepared from 2,2'4,4'6,6'-hexamethyl 3,3'-diaminobiphenyl (3,3'-M₂ DAM) and aliphatic or aromatic diacids. 3,3'-M₂ DAM and a mixture of other aliphatic or aromatic diamines may also be suitably used to react with the diacids. These novel polyamides and copolyamides are useful in preparing molded articles, fibers, films, laminates and coatings.

BACKGROUND

It is known to make polyamides from acids and diamines. British patent specification No. 570,858 discloses various processes for making fiber forming polymers; however, it is clear that the use of 3,3'-M₂ DAM to form polyamides and copolyamides useful as moldings, fibers, films, laminates and coatings has not been contemplated in the prior art.

The general object of this invention is to provide novel polyamides based on 3,3'-M₂ DAM moieties and aromatic or aliphatic acids or their halide derivatives. Another object is to provide novel copolyamides based on 3,3'-M₂ DAM moieties and another aromatic or aliphatic diamine and aromatic or aliphatic acids. A more specific object of this invention is to provide polyamides and copolyamides from 3,3'-M₂ DAM moieties and aliphatic, cycloaliphatic, araliphatic and aromatic diamine moieties and aromatic and aliphatic diacids. Another object is to provide a process for the manufacture of copolyamides and polyamides from 3,3'-M₂ DAM and diacids or 3,3'-M₂ DAM and other diamines and diacids.

We have found that novel polyamides and copolyamides can be formed by reacting the 3,3'-M₂ DAM with aromatic or aliphatic diacids. We have also found that 3,3'-M₂ DAM can be replaced up to 90 percent by other aliphatic or aromatic diamines and the resulting mixture reacted with aromatic or aliphatic diacids. 3,3'-M₂ DAM or a mixture of 3,3'-M₂ DAM and other aromatic or aliphatic diamines react readily with diacids to form high molecular weight polyamides. In the novel process both aliphatic and aromatic diacids can be polymerized with 3,3'-M₂ DAM or 3,3'-M₂ DAM and another diamine in the melt to form high molecular weight polyamide. Our process for the manufacture of the novel polyamides and copolyamides comprises reacting 3,3'-M₂ DAM with an aromatic or aliphatic diacid or alternatively a mixture or 3,3'-M₂ DAM and another diamine can be reacted with one or more diacids. The molecular ratio of the total diamine moieties may be in the range of 0.97/1.03 to 1.03/0.97 preferably in the range of 1.00 to 1.00 to the total diacid moieties. In a suitable method the reaction is conducted as a batch reaction at a temperature of about 0° to 100° C. for a period of about 0.01 to 2.0 hours in a nitrogen or halogen containing organic polar solvent such as 1-methyl-2-pyrrolidinone, N,N-dimethylacetamide, pyridine, chloroform, or methylenechloride. The polycondensation can also be carried out as a continuous process. The polycondensation can suitably be carried out at a temperature of 200° to 350° C. preferably at a temperature of about 225° to 300° C. The order of addition of the reactants is not critical and all the reactants can be added simultaneously in any order desired. The novel polyamides and copolyamides of this invention have the following structure for polyamides containing only 3,3'-M₂ DAM. ##STR1## Polyamides and copolyamides containing both 3,3'-M₂ DAM and another diamine have the following structure: ##STR2## R can be the --CH₂ -group containing from 0 to 20 repeating units. The preferred aliphatic groups are CH₂ taken twice, four times or ten times. Suitable aromatic diacids have the following structures: ##STR3## and are derived from terephthalic acid, isophthalic acid and 2,6-naphthlylemedicarboxylic acid. In the second structure R has the same values as for the first, but R', meaning the moiety derived from the other diamine may be a divalent aliphatic hydrocarbon of 2 to 18 carbon atoms or an aromatic hydrocarbon from 8 to 20 carbon atoms or an aromatic hydrocarbon radical containing from 6 to 10 carbon atoms joined directly or by stable linkage comprising from 6 to 20 carbon atoms, or an aromatic hydrocarbon radical containing from 6 to 10 carbon atoms joined directly or by stable linkage comprising --O--, methylene ##STR4## The radical R' is derived from aliphatic, araliphatic or cycloaliphatic diamines such as ethylenediamine, propylenediamine, 2,2-dimethylpropylene diamine, tetramethylene diamine, hexamethylene diamine, octamethylenediamine, nonamethylene diamine, decamethylene diamine, dodecamethylene diamine, 4,4'-diaminodicyclohexylethane, xylylene diamine and bis (aminomethyl) cyclohexane. Suitable aromatic diamines useful in our process include para- and meta-phenylenediamine, bis (4-aminophenyl)ether, thiobis (aniline), sulfonylbis (aniline), diaminobenzophenone, methylenebis (aniline), benzidine, 1,5-diaminonaphthalene, oxybis (2-methylaniline), thiobis (2-methylaniline), and the like. Examples of other useful aromatic primary diamines are set out in U.S. Pat. No. 3,494,890 (1970) and U.S. Pat. No. 4,016,140 (1972) both incorporated herein by reference. The preferred diamines are 1,6 hexanediamine, 1,12 dodecane diamine and bis (4-aminophenyl) ether.

In some cases the polyamides may be further polymerized under "solid state polymerization" conditions. The term solid state polymerization refers to chain extensions of polymer particles under conditions where the polymer particles retain their solid form and do not become a fluid mass. The solid state polymerization can be carried out below the melting point of the polyamide and can be conducted in several ways. However all techniques require heating the ground or pelletized polyamide below the melting point of the polyamide, generally at a temperature of about 150° to 250° C. while either sparging with an inert gas such as nitrogen or operating under vacuum. In cases where the polyamides have a low melt temperature, they can be polymerized in the melt under vacuum in thin sections or using thin film reactors known in the art.

Injection molding of the novel polyamide and copolyamide is accompanied by injecting the polyamide into a mold maintained at a temperature of about 23° C. to 200° C. In this process a 20 second to 1 minute cycle is used with a barrel temperature of about 200° C. to 350° C. The latter will vary depending on the Tg of the polymer being molded.

The novel polyamides and copolyamides have excellent thermal properties and can readily be molded in useful articles or formed in fibers, films, laminates or coatings. The polyamides have good tensile strength and are useful in engineering plastics operations. The limiting oxygen index of 45 percent indicates inherent resistance to burning. Infrared spectra of the polyamides and copolyamides have confirmed the copolyamide and polyamide structure. Thermal analysis of the polyamides and copolyamides by thermal gravimetric analysis shows excellent stability. Glass transition temperature, Tg, of the polyamides and copolyamides varied with the particular diamine and diacid used. Values range from a Tg of 171° C. to 364° C. We have found that the mechanical properties of the polyamides and copolyamides of this invention are improved by the addition of reinforcing materials. Suitable reinforcing material includes glass fibers, glass beads, industrial materials such as talc, or graphite or mixtures of these. Advantageously, polyamides contain from about 25 to 60 percent by weight of the polyamide. In the preferred range the polyamides and copolyamides contain about 30 to about 40 percent by weight of the glass fibers, glass beads, industrial minerals such as talc, or graphite or mixtures thereof. The glass fibers are made of alkali-free boron-silicate glass or alkali containing C-glass. The thickness of the fiber is suitably on the average between 3 um and 30 um. It is possible to use both long fibers with average lengths of from 5 to 50 mm and also short fibers of average filament length from 0.05 to 5 mm. In principle, any standard commercial-grade fibers, especially glass fibers, may be used however, the glass transition temperature of the polyamides and copolyamides is at least 171° C. Glass beads ranging from 5 um to 50 um in diameter may also be used as a reinforcing material. The reinforced polyamides and copolyamides may be prepared in various ways. For example, so-called roving endless glass fiber strands are coated with the polyamide and copolyamide melt and subsequently granulated. The cut fibers or glass beads may also be mixed with granulated polyamide and copolyamide and resulting mixture melted in a conventional extruder, or alternatively the fiber may be directly introduced into the polyamide melt through a suitable inlet into the extruder. Injection molding of the novel glass filled polyamide and copolyamide is accomplished by injecting the polyamide or copolyamide into a mold maintained at a temperature of about 100° to 200° C.

In this process a 25 to 28 second cycle is used with a barrel temperature of about 600° to 650° F. The injection molding conditions are given in Table I.

                  TABLE I                                                          ______________________________________                                         Mold Temperature  100° F. to 200° F.                             Injection Pressure                                                                               15,000 to 19,000 psi and                                                       held for 1 to 3 seconds                                      Back Pressure     100 to 220 psi                                               Cycle Time        25 to 28 seconds                                             Extruder:                                                                      Nozzle Temperature                                                                               600° F. to 630° F.                             Barrels:                                                                       Front heated to   600° F. to 630° F.                             Screw:                                                                         20 to 25 revo-                                                                 lutions/minute                                                                 ______________________________________                                    

The following examples illustrate the preferred embodiment of the invention. It will be understood that the examples are for illustrative purposes only and do not purport to be wholly definitive with respect to conditions or scope of the invention.

EXAMPLE 1

To a rapidly stirring solution of 10.20 g (0.0381 mole) of 3,3'-M₂ DAM, 8.39 g (0.0829 mole) of triethylamine, and 400 ml of methylenechloride in a Waring blender was added a solution of 7.65 g (0.377 mole) of terephthaloyl chloride dissolved in 200 ml of methylenechloride. Mixing was continued for two minutes. The solid polyamide was filtered, washed with water, and dried to give 14.88 g (99 percent yield) of product. Inherent viscosity of the product was 0.42 dl/g measured at 30° C. in a solvent of 60/40 phenol/tetrachloroethane (P/TCE) by weight and a concentration of 0.4 g/dl. The glass transition temperature was 335° C. measured on a Perkin-Elmer DSC-2 with a heating rate of 20° C./minute. TGA analysis showed 1 percent weight loss occurring at 406° C.

EXAMPLE 2

To a rapidly stirring solution of 10.20 g (0.0381 mole) of 3,3'-M₂ DAM, 8.39 g (0.0829 mole) of triethylamine, and 400 ml of methylenechloride in a Waring blender was added a solution of 7.65 (0.0377 mole) of isophthaloyl chloride dissolved in 200 ml of methylenechloride. Mixing was continued for two minutes. The solid polyamide was filtered, washed with water, and dried to give 14.67 g (98 percent yield) of product. The polyamide had a 0.35 dl/g inherent viscosity in P/TCE and a 298° C. glass transition temperature. Initial weight loss (1 percent) occurred at 391° C.

EXAMPLE 3

To a rapidly stirring solution of 10.64 g (0.0397 mole) of 3,3'-M₂ DAM, 8.84 g (0.0873 mole) of triethylamine, and 400 ml of methylenechloride in a Waring blender was added a solution of 7.27 g (0.397 mole) of adipoyl chloride dissolved in 200 ml of methylenechloride. Mixing was continued for two minutes. The solid polyamide was filtered, washed with water, and dried to give 13.66 g (91 percent yield) of product. The polyamide had a 0.45 dl/g inherent viscosity in P/TCE and a 180° C. glass transition temperature.

EXAMPLE 4

To a rapidly stirring solution of 5.00 g (0.0187 mole) of 3,3'-M₂ DAM, 3.25 g (0.0411 mole) of pyridine, and 400 ml of methylenechloride in a Waring blender was added a solution of 1.90 g (0.0093 mole) of isophthaloyl chloride and 1.90 g (0.0093 mole) of terephthaloyl chloride dissolved in 200 ml of methylenechloride. Mixing was continued for two minutes. The solid copolyamide was filtered, washed with water, and dried to give 7.22 g (98 percent yield) of product. The copolyamide had a 0.37 dl/g inherent viscosity in P/TCE and a 315° C. glass transition temperature. 

We claim:
 1. An injection moldable polyamide comprising the following recurring structure: ##STR5## wherein R is a divalent aliphatic or aromatic hydrocarbon radical or a mixture of hydrocarbon radicals and the polyamide has a glass transition temperature of excess of 171° C.
 2. The polyamide of claim 1 wherein R is an aliphatic hydrocarbon from 2 to 18 carbon atoms.
 3. The polyamide of claim 1 wherein R is an aromatic hydrocarbon from 6 to 20 carbon atoms.
 4. The polyamide of claim 1 wherein the aromatic hydrocarbon radical contains from 6 to 10 carbon atoms joined directly or by stable linkage. comprising --O--, methylene ##STR6## --SO--, --SO₂ -- or --S-- radicals.
 5. The polyamide of claim 1 wherein the polyamide is in the form of a molded object.
 6. The polyamide of claim 1 wherein the polyamide is in the form of a laminate.
 7. The polyamide of claim 1 wherein the polyamide is in the form of a fiber.
 8. The polyamide of claim 1 wherein the polyamide is in the form of a film.
 9. The polyamide of claim 1 wherein R is --(CH₂)₁₀ --.
 10. The polyamide of claim 9 wherein the polyamide is in the form of a molded object.
 11. The polyamide of claim 9 wherein the polyamide is in the form of a film.
 12. The polyamide of claim 9 wherein the polyamide is in the form of a fiber.
 13. The polyamide of claim 9 wherein the polyamide is in the form of a laminate.
 14. The polyamide of claim 1 wherein R is --(CH₂)₄ --.
 15. The polyamide of claim 14 wherein the polyamide is in the form of a molded object.
 16. The polyamide of claim 14 wherein the polyamide is in the form of a film.
 17. The polyamide of claim 14 wherein the polyamide is in the form of a fiber.
 18. The polyamide of claim 14 wherein the polyamide is in the form of a laminate.
 19. The polyamide of claim 1 wherein R is: ##STR7##
 20. The polyamide of claim 19 wherein the polyamide is in the form of a molded object.
 21. The polyamide of claim 19 wherein the polyamide is in the form of a film.
 22. The polyamide of claim 19 wherein the polyamide is in the form of a fiber.
 23. The polyamide of claim 19 wherein the polyamide is in the form of a laminate.
 24. The polyamide of claim 1 wherein R is: ##STR8##
 25. The polyamide of claim 24 wherein the polyamide is in the form of a molded object.
 26. The polyamide of claim 24 wherein the polyamide is in the form of a film.
 27. The polyamide of claim 24 wherein the polyamide is in the form of a fiber.
 28. The polyamide of claim 24 wherein the polyamide is in the form of a laminate.
 29. The polyamide of claim 1 wherein R is a mixture of: ##STR9## wherein the weight range of the aromatic moieties is about 99:1 to 1:99.
 30. The polyamide of claim 29 wherein the polyamide is in the form of a molded object.
 31. The polyamide of claim 29 wherein the polyamide is in the form of a film.
 32. The polyamide of claim 29 wherein the polyamide is in the form of a fiber.
 33. The polyamide of claim 29 wherein the polyamide is in the form of a laminate.
 34. An injection moldable copolyamide comprising the following recurring structure: ##STR10## wherein R and R' are the same or different aliphatic or aromatic hydrocarbons and the copolyamide has a glass transition temperature in excess of 171° C.
 35. The copolyamide of claim 34 wherein R and R' are aromatic hydrocarbons from 6 to 20 carbon atoms or aliphatic hydrocarbons from 2 to 18 carbon atoms or a mixture of aliphatic and aromatic hydrocarbons.
 36. The copolyamide of claim 35 wherein R and R' are --(CH₂)₈ --.
 37. The copolyamide of claim 36 wherein the copolyamide is in the form of a molded object.
 38. The copolyamide of claim 36 wherein the copolyamide is in the form of a film.
 39. The copolyamide of claim 36 wherein the copolyamide is in the form of a fiber.
 40. The copolyamide of claim 36 wherein the copolyamide is in the form of a laminate.
 41. The copolyamide of claim 34 wherein R and R' are --(CH₂)₄ --.
 42. The copolyamide of claim 41 wherein the copolyamide is in the form of a molded object.
 43. The copolyamide of claim 41 wherein the copolyamide is in the form of a film.
 44. The copolyamide of claim 41 wherein the copolyamide is in the form of a fiber.
 45. The copolyamide of claim 41 wherein the copolyamide is in the form of a laminate.
 46. The copolyamide of claim 35 wherein R and R' are: ##STR11##
 47. The copolyamide of claim 46 wherein the copolyamide is in the form of a molded object.
 48. The copolyamide of claim 46 wherein the copolyamide is in the form of a film.
 49. The copolyamide of claim 46 wherein the copolyamide is in the form of a fiber.
 50. The copolyamide of claim 46 wherein the copolyamide is in the form of a laminate.
 51. The copolyamide of claim 35 wherein the R and R' are: ##STR12##
 52. The copolyamide of claim 51 wherein the copolyamide is in the form of a molded object.
 53. The copolyamide of claim 51 wherein the copolyamide is in the form of a film.
 54. The copolyamide of claim 51 wherein the copolyamide is in the form of a fiber.
 55. The copolyamide of claim 51 wherein the copolyamide is in the form of a laminate.
 56. The copolyamide of claim 35 wherein R and R' are a mixture of: ##STR13## wherein the weight range of the aromatic moieties is about 99:1 to 1:99.
 57. The copolyamide of claim 56 wherein the copolyamide is in the form of a molded object.
 58. The copolyamide of claim 56 wherein the copolyamide is in the form of a film.
 59. The copolyamide of claim 56 wherein the copolyamide is in the form of a fiber.
 60. The copolyamide of claim 56 wherein the copolyamide is in the form of a laminate.
 61. The copolyamide of claim 35 wherein R is ##STR14## and R' is --(CH₂)₆ --.
 62. The copolyamide of claim 61 wherein the copolyamide is in the form of a molded object.
 63. The copolyamide of claim 61 wherein the copolyamide is in the form of a film.
 64. The copolyamide of claim 61 wherein the copolyamide is in the form of a laminate. 